Treatment training manual

5. 6 PCP

Type of infection

PCP stands for pneumocystis pneumonia. It is caused by a common organism that behaves like a fungusPCP is mainly a lung infection – a pneumonia.

The full name is pneumocystis jiroveci (pronounced: yee-row-vet-zee). PCP used to be called pneumocystis carinii.

The risk of PCP is higher when the CD4 count is less than 200 cells/mm3. It is rare at higher CD4 counts. Most cases of PCP are when the CD4 is less than 100 cells/mm3.

Main symptoms

  • Difficulty breathing, being short of breath, tightness in the chest.
  • Dry cough.
  • Feeling tired, fever and weight loss.

Symptoms in someone living with HIV who has a low CD4 count are sufficient to start treatment.

PCP can sometimes be in other places, like the bones and eye. This is rare.


Sputum is tested for a definite diagnosis. This can be from a bronchoscopy. Or from  ‘induced’ sputum. This involves breathing a salty mist that brings up fluid from deeper in the lungs.


  • First-line treatment: co-trimoxazole (Septrin, Bactrim, TMP-SMX).
    Co-trimoxazole is made up of two antibiotics: trimethoprim (TMP) and sulphamethoxazole (SMX). Standard doses are TMP 15–20 mg per kg body weight a day + SMX 75 mg per kg body weight a day, by continuous drip. Or 3–4 injections a day for 3–4 days, followed by tablets.
  • Other treatments: trimethoprim plus dapsone, pentamidine, trimetrexate, atovaquone and clindamycin plus primaquine.


Prophylaxis is the term for taking a medicine to prevent becoming ill.

Even if you don’t have active PCP, daily co-trimoxazole is recommended for many people.

It is also recommended for babies to protect against HIV after birth.

In some countries it is given to everyone who is living with HIV. In other countries, it is only given when the CD4 count is less than 350, or even (including the UK) only when the CD4 count is less than 200.

This means everyone with a CD4 count below 200 cells/mm3 should take daily cotromoxazole pill to prevent PCP. This is even if you are taking HIV treatment (ART).

In most countries, prophylaxis can be stopped after the CD4 count has increased to over 350 or 200 on ART. Sometimes it can be stopped a bit earlier if there are no symptoms.

Co-trimoxazole (Septrin or Bactrim) at 960 mg/day is the most widely used prophylaxis. The 960 mg includes160 mg TMP + 800 mg SMX)

Other prophylaxis used when co-trimoxazole causes side effects or if resistance has developed: dapsone (often has side effect in people who cannot tolerate co-trimoxazole), aerosolised pentamidine (every 2–4 weeks), atovaquone, sulphadiazine plus pyrimethamine and dapsone plus pyrimethamine.

Prophylaxis for PCP with co-trimoxazole protects against other infections including toxoplasmosis.


Last updated: 1 January 2023.